The QStringRef class provides a thin wrapper around QString 子字符串。 更多...
| 头： | #include <QStringRef> |
| qmake: | QT += core |
| Since: | Qt 4.3 |
注意： 此类的所有函数 可重入 .
| typedef | const_iterator |
| typedef | const_reverse_iterator |
| QStringRef () | |
| QStringRef (const QString * string , int position , int length ) | |
| QStringRef (const QString * string ) | |
| QStringRef (const QStringRef & other ) | |
| QStringRef (QStringRef && other ) | |
| ~QStringRef () | |
| QStringRef | appendTo (QString * string ) const |
| const QChar | at (int position ) const |
| const_iterator | begin () const |
| const_iterator | cbegin () const |
| const_iterator | cend () const |
| void | chop (int n ) |
| void | clear () |
| int | compare (const QStringRef & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (QLatin1String other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (const QByteArray & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | compare (const QString & other , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| const_iterator | constBegin () const |
| const QChar * | constData () const |
| const_iterator | constEnd () const |
| bool | contains (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | contains (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count () const |
| int | count (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | count (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| const_reverse_iterator | crbegin () const |
| const_reverse_iterator | crend () const |
| const QChar * | data () const |
| const_iterator | end () const |
| bool | endsWith (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | endsWith (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (const QString & str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (QChar ch , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (QLatin1String str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | indexOf (const QStringRef & str , int from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | isEmpty () const |
| bool | isNull () const |
| bool | isRightToLeft () const |
| int | lastIndexOf (const QString & str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (QChar ch , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (QLatin1String str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| int | lastIndexOf (const QStringRef & str , int from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QStringRef | left (int n ) const |
| int | length () const |
| int | localeAwareCompare (const QStringRef & other ) const |
| int | localeAwareCompare (const QString & other ) const |
| QStringRef | mid (int position , int n = -1) const |
| int | position () const |
| const_reverse_iterator | rbegin () const |
| const_reverse_iterator | rend () const |
| QStringRef | right (int n ) const |
| int | size () const |
| QVector<QStringRef> | split (const QString & sep , QString::SplitBehavior behavior = QString::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| QVector<QStringRef> | split (QChar sep , QString::SplitBehavior behavior = QString::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (const QString & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (QLatin1String str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (QChar ch , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| bool | startsWith (const QStringRef & str , Qt::CaseSensitivity cs = Qt::CaseSensitive) const |
| const QString * | string () const |
| double | toDouble (bool * ok = Q_NULLPTR) const |
| float | toFloat (bool * ok = Q_NULLPTR) const |
| int | toInt (bool * ok = Q_NULLPTR, int base = 10) const |
| QByteArray | toLatin1 () const |
| QByteArray | toLocal8Bit () const |
| long | toLong (bool * ok = Q_NULLPTR, int base = 10) const |
| qlonglong | toLongLong (bool * ok = Q_NULLPTR, int base = 10) const |
| short | toShort (bool * ok = Q_NULLPTR, int base = 10) const |
| QString | toString () const |
| uint | toUInt (bool * ok = Q_NULLPTR, int base = 10) const |
| ulong | toULong (bool * ok = Q_NULLPTR, int base = 10) const |
| qulonglong | toULongLong (bool * ok = Q_NULLPTR, int base = 10) const |
| ushort | toUShort (bool * ok = Q_NULLPTR, int base = 10) const |
| QVector<uint> | toUcs4 () const |
| QByteArray | toUtf8 () const |
| QStringRef | trimmed () const |
| void | truncate (int position ) |
| const QChar * | unicode () const |
| bool | operator!= (const char * s ) const |
| bool | operator< (const char * s ) const |
| bool | operator<= (const char * s ) const |
| QStringRef & | operator= (QStringRef && other ) |
| QStringRef & | operator= (const QStringRef & other ) |
| QStringRef & | operator= (const QString * string ) |
| bool | operator== (const char * s ) const |
| bool | operator> (const char * s ) const |
| bool | operator>= (const char * s ) const |
| QChar | operator[] (int position ) const |
| int | compare (const QStringRef & s1 , const QString & s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | compare (const QStringRef & s1 , const QStringRef & s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | compare (const QStringRef & s1 , QLatin1String s2 , Qt::CaseSensitivity cs = Qt::CaseSensitive) |
| int | localeAwareCompare (const QStringRef & s1 , const QString & s2 ) |
| int | localeAwareCompare (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator< (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator<= (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator== (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator== (const QString & s1 , const QStringRef & s2 ) |
| bool | operator== (QLatin1String s1 , const QStringRef & s2 ) |
| bool | operator> (const QStringRef & s1 , const QStringRef & s2 ) |
| bool | operator>= (const QStringRef & s1 , const QStringRef & s2 ) |
The QStringRef class provides a thin wrapper around QString 子字符串。
QStringRef provides a read-only subset of the QString API.
A string reference explicitly references a portion of a string () with a given size (), starting at a specific position ()。调用 toString () returns a copy of the data as a real QString 实例。
This class is designed to improve the performance of substring handling when manipulating substrings obtained from existing QString 实例。 QStringRef avoids the memory allocation and reference counting overhead of a standard QString by simply referencing a part of the original string. This can prove to be advantageous in low level code, such as that used in a parser, at the expense of potentially more complex code.
For most users, there are no semantic benefits to using QStringRef 而不是 QString since QStringRef requires attention to be paid to memory management issues, potentially making code more complex to write and maintain.
警告： A QStringRef is only valid as long as the referenced string exists. If the original string is deleted, the string reference points to an invalid memory location.
We suggest that you only use this class in stable code where profiling has clearly identified that performance improvements can be made by replacing standard string operations with the optimized substring handling provided by this class.
另请参阅 隐式共享类 .
此 typedef 提供 STL 样式 const 迭代器为 QStringRef .
该 typedef 在 Qt 5.4 引入。
另请参阅 QStringRef::const_reverse_iterator .
This typedef provides an STL-style const reverse iterator for QStringRef .
该 typedef 在 Qt 5.7 引入。
另请参阅 QStringRef::const_iterator .
Constructs an empty string reference.
Constructs a string reference to the range of characters in the given string specified by the starting position and length in characters.
警告： This function exists to improve performance as much as possible, and performs no bounds checking. For program correctness, position and length must describe a valid substring of string .
This means that the starting position must be positive or 0 and smaller than string 's length, and length must be positive or 0 but smaller than the string's length minus the starting position ; i.e, 0 <= position < string-> length () and 0 <= length <= string-> length () - position must both be satisfied.
Constructs a string reference to the given string .
构造副本为 other string reference.
移动拷贝构造函数。
Destroys the string reference.
Since this class is only used to refer to string data, and does not take ownership of it, no memory is freed when instances are destroyed.
Appends the string reference to string , and returns a new reference to the combined string data.
返回字符按给定索引 position in the string reference.
The position must be a valid index position in the string (i.e., 0 <= position < size ()).
返回常量 STL 样式迭代器 指向字符串中的首个字符。
该函数在 Qt 5.4 引入。
另请参阅 cbegin (), constBegin (), end (), constEnd (), rbegin ()，和 rend ().
如同 begin ().
该函数在 Qt 5.4 引入。
另请参阅 begin (), constBegin (), cend (), constEnd (), rbegin ()，和 rend ().
如同 end ().
该函数在 Qt 5.4 引入。
另请参阅 end (), constEnd (), cbegin (), constBegin (), rbegin ()，和 rend ().
移除 n 个字符从字符串末尾起。
若 n >= size ()，结果为空字符串；若 n 为负，相当于传递 0。
该函数在 Qt 5.8 引入。
另请参阅 QString::chop () 和 truncate ().
Clears the contents of the string reference by making it null and empty.
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
, const
QString
&
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
该函数在 Qt 4.5 引入。
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
该函数在 Qt 4.5 引入。
另请参阅 QString::compare ().
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
该函数在 Qt 4.5 引入。
另请参阅 QString::compare ().
这是重载函数。
Compares this string with other and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other byte array, interpreted as a UTF-8 sequence.
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
该函数在 Qt 5.8 引入。
另请参阅 QString::compare ().
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
相当于
compare(*this, other, cs)
.
该函数在 Qt 4.5 引入。
另请参阅 QString::compare ().
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
, const
QStringRef
&
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
这是重载函数。
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
该函数在 Qt 4.5 引入。
[static]
int
QStringRef::
compare
(const
QStringRef
&
s1
,
QLatin1String
s2
,
Qt::CaseSensitivity
cs
= Qt::CaseSensitive)
这是重载函数。
比较字符串 s1 采用字符串 s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
若 cs is Qt::CaseSensitive , the comparison is case sensitive; otherwise the comparison is case insensitive.
该函数在 Qt 4.5 引入。
如同 begin ().
该函数在 Qt 5.9 引入。
另请参阅 begin (), cend (), constEnd (), rbegin ()，和 rend ().
如同 unicode ().
如同 end ().
该函数在 Qt 5.9 引入。
另请参阅 end (), cend (), cbegin (), constBegin (), rbegin ()，和 rend ().
返回
true
if this string reference contains an occurrence of the string
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
此函数重载 contains ().
返回
true
若此字符串包含出现字符
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
此函数重载 contains ().
返回
true
if this string reference contains an occurrence of the string
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
此函数重载 contains ().
返回
true
if this string reference contains an occurrence of the string reference
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
Returns the number of characters referred to by the string reference. Equivalent to size () 和 length ().
返回 (潜在重叠) 出现数对于字符串 str in this string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::count (), contains ()，和 indexOf ().
此函数重载 count ().
Returns the number of occurrences of the character ch in the string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::count (), contains ()，和 indexOf ().
此函数重载 count ().
Returns the number of (potentially overlapping) occurrences of the string reference str in this string reference.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::count (), contains ()，和 indexOf ().
如同 rbegin ().
该函数在 Qt 5.7 引入。
另请参阅 begin (), rbegin ()，和 rend ().
如同 rend ().
该函数在 Qt 5.7 引入。
另请参阅 end (), rend ()，和 rbegin ().
如同 unicode ().
返回常量 STL 样式迭代器 pointing to the imaginary character after the last character in the list.
该函数在 Qt 5.4 引入。
另请参阅 cbegin (), constBegin (), end(), constEnd (), rbegin ()，和 rend ().
返回
true
if the string reference ends with
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::endsWith () 和 startsWith ().
此函数重载 endsWith ().
该函数在 Qt 4.8 引入。
另请参阅 QString::endsWith () 和 endsWith ().
此函数重载 endsWith ().
返回
true
if the string reference ends with
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::endsWith () 和 endsWith ().
此函数重载 endsWith ().
该函数在 Qt 4.8 引入。
另请参阅 QString::endsWith () 和 endsWith ().
Returns the index position of the first occurrence of the string str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
若 from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.
该函数在 Qt 4.8 引入。
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
此函数重载 indexOf ().
Returns the index position of the first occurrence of the character ch in the string reference, searching forward from index position from . Returns -1 if ch could not be found.
该函数在 Qt 4.8 引入。
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
Returns the index position of the first occurrence of the string str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
若 from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.
该函数在 Qt 4.8 引入。
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
此函数重载 indexOf ().
Returns the index position of the first occurrence of the string reference str in this string reference, searching forward from index position from . Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::indexOf (), lastIndexOf (), contains ()，和 count ().
返回
true
if the string reference has no characters; otherwise returns
false
.
A string reference is empty if its size is zero.
另请参阅 size ().
返回
true
if
string
() returns a null pointer or a pointer to a null string; otherwise returns
true
.
另请参阅 size ().
返回
true
if the string is read right to left.
该函数在 Qt 5.9 引入。
另请参阅 QString::isRightToLeft ().
Returns the index position of the last occurrence of the string str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
此函数重载 lastIndexOf ().
Returns the index position of the last occurrence of the character ch , searching backward from position from .
该函数在 Qt 4.8 引入。
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
此函数重载 lastIndexOf ().
Returns the index position of the last occurrence of the string str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
此函数重载 lastIndexOf ().
Returns the index position of the last occurrence of the string reference str in this string reference, searching backward from index position from 。若 from is -1 (default), the search starts at the last character; if from is -2, at the next to last character and so on. Returns -1 if str 找不到。
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::lastIndexOf (), indexOf (), contains ()，和 count ().
Returns a substring reference to the n leftmost characters of the string.
若 n >= size (), or less than zero, a reference to the entire string is returned.
该函数在 Qt 5.2 引入。
另请参阅 right (), mid ()，和 startsWith ().
Returns the number of characters referred to by the string reference. Equivalent to size () 和 count ().
[static]
int
QStringRef::
localeAwareCompare
(const
QStringRef
&
s1
, const
QString
&
s2
)
比较 s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
On macOS and iOS, this function compares according the "Order for sorted lists" setting in the International prefereces panel.
该函数在 Qt 4.5 引入。
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
该函数在 Qt 4.5 引入。
这是重载函数。
Compares this string with the other string and returns an integer less than, equal to, or greater than zero if this string is less than, equal to, or greater than the other 字符串。
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
该函数在 Qt 4.5 引入。
[static]
int
QStringRef::
localeAwareCompare
(const
QStringRef
&
s1
, const
QStringRef
&
s2
)
这是重载函数。
比较 s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2 .
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
该函数在 Qt 4.5 引入。
Returns a substring reference to n 个字符对于此字符串，起始于指定 position .
若 position exceeds the length of the string, a null reference is returned.
If there are less than n characters available in the string, starting at the given position ，或者若 n is -1 (default), the function returns all characters from the specified position onwards.
该函数在 Qt 5.2 引入。
Returns the starting position in the referenced string that is referred to by the string reference.
返回常量 STL-style reverse iterator pointing to the first character in the string, in reverse order.
该函数在 Qt 5.7 引入。
另请参阅 begin (), crbegin ()，和 rend ().
返回 STL-style reverse iterator pointing to one past the last character in the string, in reverse order.
该函数在 Qt 5.7 引入。
另请参阅 end (), crend ()，和 rbegin ().
Returns a substring reference to the n rightmost characters of the string.
若 n >= size (), or less than zero, a reference to the entire string is returned.
该函数在 Qt 5.2 引入。
另请参阅 left (), mid ()，和 endsWith ().
Returns the number of characters referred to by the string reference. Equivalent to length () 和 count ().
Splits the string into substrings references wherever sep occurs, and returns the list of those strings.
见 QString::split () for how sep , behavior and cs interact to form the result.
注意： All references are valid as long this string is alive. Destroying this string will cause all references be dangling pointers.
该函数在 Qt 5.4 引入。
这是重载函数。
该函数在 Qt 5.4 引入。
返回
true
if the string reference starts with
str
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::startsWith () 和 endsWith ().
此函数重载 startsWith ().
该函数在 Qt 4.8 引入。
另请参阅 QString::startsWith () 和 endsWith ().
此函数重载 startsWith ().
返回
true
if the string reference starts with
ch
；否则返回
false
.
若 cs is Qt::CaseSensitive (default), the search is case sensitive; otherwise the search is case insensitive.
该函数在 Qt 4.8 引入。
另请参阅 QString::startsWith () 和 endsWith ().
此函数重载 startsWith ().
该函数在 Qt 4.8 引入。
另请参阅 QString::startsWith () 和 endsWith ().
Returns a pointer to the string referred to by the string reference, or 0 if it does not reference a string.
另请参阅 unicode ().
Returns the string converted to a
double
值。
Returns 0.0 if the conversion fails.
If a conversion error occurs,
*
ok
被设为
false
；否则
*
ok
被设为
true
.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toDouble ()
For historic reasons, this function does not handle thousands group separators. If you need to convert such numbers, use QLocale::toDouble ().
该函数在 Qt 5.1 引入。
另请参阅 QString::toDouble ().
Returns the string converted to a
float
值。
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
. Returns 0.0 if the conversion fails.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toFloat ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toFloat ().
Returns the string converted to an
int
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toInt ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toInt ().
Returns a Latin-1 representation of the string as a QByteArray .
The returned byte array is undefined if the string contains non-Latin1 characters. Those characters may be suppressed or replaced with a question mark.
该函数在 Qt 4.8 引入。
另请参阅 toUtf8 (), toLocal8Bit ()，和 QTextCodec .
Returns the local 8-bit representation of the string as a QByteArray . The returned byte array is undefined if the string contains characters not supported by the local 8-bit encoding.
QTextCodec::codecForLocale () is used to perform the conversion from Unicode. If the locale encoding could not be determined, this function does the same as toLatin1 ().
If this string contains any characters that cannot be encoded in the locale, the returned byte array is undefined. Those characters may be suppressed or replaced by another.
该函数在 Qt 4.8 引入。
另请参阅 toLatin1 (), toUtf8 ()，和 QTextCodec .
Returns the string converted to a
long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toLong()
该函数在 Qt 5.1 引入。
另请参阅 QString::toLong ().
Returns the string converted to a
long long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toLongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toLongLong ().
Returns the string converted to a
short
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toShort ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toShort ().
Returns a copy of the string reference as a QString 对象。
If the string reference is not a complete reference of the string (meaning that position () is 0 and size () 等于 string ()-> size ()), this function will allocate a new string to return.
另请参阅 string ().
Returns the string converted to an
无符号 int
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toUInt ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toUInt ().
Returns the string converted to an
unsigned long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toULongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toULong ().
Returns the string converted to an
unsigned long long
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toULongLong ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toULongLong ().
Returns the string converted to an
unsigned short
使用基
base
, which is 10 by default and must be between 2 and 36, or 0. Returns 0 if the conversion fails.
If a conversion error occurs, *
ok
被设为
false
; otherwise *
ok
被设为
true
.
若 base is 0, the C language convention is used: If the string begins with "0x", base 16 is used; if the string begins with "0", base 8 is used; otherwise, base 10 is used.
The string conversion will always happen in the 'C' locale. For locale dependent conversion use QLocale::toUShort ()
该函数在 Qt 5.1 引入。
另请参阅 QString::toUShort ().
Returns a UCS-4/UTF-32 representation of the string as a QVector <uint>.
UCS-4 is a Unicode codec and therefore it is lossless. All characters from this string will be encoded in UCS-4. Any invalid sequence of code units in this string is replaced by the Unicode's replacement character (
QChar::ReplacementCharacter
, which corresponds to
U+FFFD
).
The returned vector is not NUL terminated.
该函数在 Qt 4.8 引入。
另请参阅 toUtf8 (), toLatin1 (), toLocal8Bit ()，和 QTextCodec .
Returns a UTF-8 representation of the string as a QByteArray .
UTF-8 is a Unicode codec and can represent all characters in a Unicode string like QString .
该函数在 Qt 4.8 引入。
另请参阅 toLatin1 (), toLocal8Bit ()，和 QTextCodec .
返回从开始到结束之间，已移除空白的字符串。
空白意味着任何字符其。
QChar::isSpace
() 返回
true
。这包括 ASCII 字符 \t、\n、\v、\f、\r、及 " "。
不像 QString::simplified ()，trimmed() 只留下内部空白。
该函数在 Qt 5.1 引入。
另请参阅 QString::trimmed ().
截取字符串按给定 position 索引。
若指定 position 索引超出字符串末尾，什么都不发生。
若 position 为负，相当于传递 0。
该函数在 Qt 5.6 引入。
另请参阅 QString::truncate ().
Returns a Unicode representation of the string reference. Since the data stems directly from the referenced string, it is not null-terminated unless the string reference includes the string's null terminator.
另请参阅 string ().
This function overloads operator!=().
The s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is not lexically equal to the parameter string
s
. Otherwise returns
false
.
This function overloads operator<().
The s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically smaller than the parameter string
s
. Otherwise returns
false
.
This function overloads operator<=().
The s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically smaller than or equal to the parameter string
s
. Otherwise returns
false
.
移动赋值运算符。
赋值 other string reference to this string reference, and returns the result.
Constructs a string reference to the given string and assigns it to this string reference, returning the result.
This function overloads operator==().
The s byte array is converted to a QStringRef using the fromUtf8() function. This function stops conversion at the first NUL character found, or the end of the byte array.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically equal to the parameter string
s
. Otherwise returns
false
.
This function overloads operator>().
The s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically greater than the parameter string
s
. Otherwise returns
false
.
此函数重载运算符 >=()。
The s const char pointer is converted to a QStringRef using the fromUtf8() function.
可以禁用此运算符通过定义
QT_NO_CAST_FROM_ASCII
when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through
QObject::tr
(), for example.
返回
true
if this string is lexically greater than or equal to the parameter string
s
. Otherwise returns
false
.
返回字符按给定索引 position in the string reference.
The position must be a valid index position in the string reference (i.e., 0 <= position < size ()).
该函数在 Qt 5.7 引入。
另请参阅 at ().
返回
true
if string reference
s1
is lexically less than string reference
s2
；否则返回
false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings using the QString::localeAwareCompare () 函数。
返回
true
if string reference
s1
is lexically less than or equal to string reference
s2
；否则返回
false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings using the QString::localeAwareCompare () 函数。
返回
true
if string reference
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
若字符串
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
若字符串
s1
is lexically equal to string reference
s2
；否则返回
false
.
返回
true
if string reference
s1
is lexically greater than string reference
s2
；否则返回
false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings using the QString::localeAwareCompare () 函数。
返回
true
if string reference
s1
is lexically greater than or equal to string reference
s2
；否则返回
false
.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings using the QString::localeAwareCompare () 函数。